1 00:00:01,920 --> 00:00:06,560 Speaker 1: Welcome to brain stuff, a production of I Heart Radio, Hey, 2 00:00:06,640 --> 00:00:10,520 Speaker 1: brain stuff, Lauren Volga bam here. Close your eyes if 3 00:00:10,560 --> 00:00:14,560 Speaker 1: it's safe to do so, and conjure up the following smells. 4 00:00:15,520 --> 00:00:19,880 Speaker 1: Burst of citrus while peeling a juicy orange, the green 5 00:00:20,120 --> 00:00:23,560 Speaker 1: piney scent of a fresh cut Christmas tree, or a 6 00:00:23,640 --> 00:00:28,200 Speaker 1: warm waft of perfume from a blooming lilac bush is 7 00:00:28,280 --> 00:00:35,320 Speaker 1: the very idea relaxing Stretching back millennia, ancient cultures like 8 00:00:35,400 --> 00:00:39,240 Speaker 1: those in China, India, and Egypt recognized that certain aromas 9 00:00:39,280 --> 00:00:43,239 Speaker 1: are deeply soothing, and folk healers have long prescribed sent 10 00:00:43,360 --> 00:00:48,120 Speaker 1: it essential oils for treating stress induced conditions like anxiety, insomnia, 11 00:00:48,200 --> 00:00:52,040 Speaker 1: and headaches. But science is still trying to figure out 12 00:00:52,200 --> 00:00:58,000 Speaker 1: exactly how and why these potent aromas produce calming physiological responses. 13 00:00:59,200 --> 00:01:03,280 Speaker 1: Our sense of smell is triggered when fragrance molecules attached 14 00:01:03,320 --> 00:01:08,360 Speaker 1: to special cilia covered olfactory nerve receptors in our nasal cavity. 15 00:01:08,640 --> 00:01:12,600 Speaker 1: Those receptors then send electrical signals directly to the olfactory 16 00:01:12,680 --> 00:01:16,039 Speaker 1: cortex of the brain, which in turn talks to the 17 00:01:16,160 --> 00:01:20,040 Speaker 1: memory and emotion centers of the brain like the hippocampus, amygdala, 18 00:01:20,160 --> 00:01:25,559 Speaker 1: and frontal cortex, and a study published in the journal 19 00:01:25,640 --> 00:01:30,680 Speaker 1: Frontiers and Behavioral Neuroscience strengthens the theory that some smells 20 00:01:30,720 --> 00:01:34,800 Speaker 1: can act like nature's own anti anxiety medication, tweaking our 21 00:01:34,840 --> 00:01:38,040 Speaker 1: brain chemistry in ways that mimic the effects of prescription 22 00:01:38,120 --> 00:01:43,920 Speaker 1: drugs like valium and diazepam. In a series of experiments, 23 00:01:44,120 --> 00:01:47,920 Speaker 1: Japanese researchers ran nice through mazes and other rodent stress 24 00:01:48,000 --> 00:01:51,760 Speaker 1: tests while exposing them to an aroma called Lanella wall. 25 00:01:52,200 --> 00:01:55,600 Speaker 1: It's the compound that gives lavender its sweet floral scent. 26 00:01:56,680 --> 00:01:59,960 Speaker 1: From previous studies, they suspected the Lunella wall would lower 27 00:02:00,040 --> 00:02:03,360 Speaker 1: anxiety levels in the mice, which it did, But the 28 00:02:03,360 --> 00:02:07,400 Speaker 1: scientists also wanted to test a hypothesis that lavender's calming 29 00:02:07,440 --> 00:02:12,320 Speaker 1: effect went straight from the mouse's nose to its neurons, 30 00:02:12,360 --> 00:02:15,880 Speaker 1: so they included mice in the study that were anasmic, 31 00:02:16,320 --> 00:02:19,919 Speaker 1: meaning they had no sense of smell. Those mice showed 32 00:02:19,960 --> 00:02:23,560 Speaker 1: no effect from exposure to Linnell wall, approving that the 33 00:02:23,600 --> 00:02:29,400 Speaker 1: olfactory system was definitely the delivery mechanism. Next, the researchers 34 00:02:29,440 --> 00:02:32,200 Speaker 1: wanted to figure out whether Lennella wall was targeting the 35 00:02:32,240 --> 00:02:34,600 Speaker 1: same receptors in the brain as some of the most 36 00:02:34,680 --> 00:02:41,480 Speaker 1: common prescription anti anxiety medications. Drugs like valium, xanex, klonopin, 37 00:02:41,560 --> 00:02:44,640 Speaker 1: and diazepam, are all members of the same drug family 38 00:02:44,880 --> 00:02:49,040 Speaker 1: called benzo diazepines. One of the causes of clinical anxiety 39 00:02:49,080 --> 00:02:53,639 Speaker 1: is overactive neuronal activity in the brain, and benzo diazepines 40 00:02:53,680 --> 00:02:57,680 Speaker 1: can inhibit or calm down neuronal activity. They do this 41 00:02:57,800 --> 00:03:02,080 Speaker 1: by binding to particular sites on rons called gammamno buttyrric 42 00:03:02,280 --> 00:03:07,160 Speaker 1: acid or GABBA receptors. The Japanese researchers made a strong 43 00:03:07,240 --> 00:03:10,119 Speaker 1: case that the smell of lavender acts on those very 44 00:03:10,320 --> 00:03:15,400 Speaker 1: same GABA receptors. They did this by treating some of 45 00:03:15,440 --> 00:03:19,120 Speaker 1: the mice with a drug that blocks GABA receptors, and 46 00:03:19,320 --> 00:03:22,960 Speaker 1: when those treated mice sniffed the lunel wall, they didn't 47 00:03:23,000 --> 00:03:28,320 Speaker 1: exhibit any calming effects. Lavender isn't the only aroma that's 48 00:03:28,360 --> 00:03:31,560 Speaker 1: been linked to the same neuron receptors as potent anti 49 00:03:31,600 --> 00:03:35,880 Speaker 1: anxiety drugs, though. A few years ago, German researchers tested 50 00:03:36,040 --> 00:03:39,680 Speaker 1: hundreds of fragrances on GABA receptors in rodents and humans, 51 00:03:40,000 --> 00:03:43,320 Speaker 1: and the big winner was jasmine, which delivered a gabba 52 00:03:43,360 --> 00:03:47,720 Speaker 1: effect as powerful as sleeping pills and sedatives. Lavender and 53 00:03:47,840 --> 00:03:51,160 Speaker 1: jasmine are the first ancient relaxation remedies to be tested 54 00:03:51,240 --> 00:03:54,840 Speaker 1: like this, but several others may share a similar nosed 55 00:03:54,880 --> 00:03:59,880 Speaker 1: brain mechanism, according to that Japanese study. Other compounds that 56 00:04:00,000 --> 00:04:03,200 Speaker 1: have shown promising anti anxiety effects in mice and men 57 00:04:03,400 --> 00:04:07,120 Speaker 1: include lemoning, one of the aroma compounds of citrus peels, 58 00:04:07,160 --> 00:04:10,360 Speaker 1: and pining, one of the aroma compounds of pine trees. 59 00:04:11,800 --> 00:04:16,520 Speaker 1: Aromas aren't universally relaxing, though, Since smells share such a 60 00:04:16,520 --> 00:04:21,080 Speaker 1: close neurological connection to memories and emotions, their physiological effects 61 00:04:21,120 --> 00:04:26,720 Speaker 1: can also be altered by our personal experiences. Like Pavlov's dogs, 62 00:04:26,720 --> 00:04:30,240 Speaker 1: our brains can be conditioned to love or hate certain 63 00:04:30,279 --> 00:04:34,720 Speaker 1: smells depending on our associations with them. For example, if 64 00:04:34,760 --> 00:04:37,440 Speaker 1: you had a negative experience at a job or as 65 00:04:37,440 --> 00:04:41,279 Speaker 1: a child scrubbing messes out with lemon scented cleanser, you 66 00:04:41,360 --> 00:04:45,919 Speaker 1: might not find the odor all that soothing. A Research 67 00:04:45,960 --> 00:04:49,160 Speaker 1: has shown that the olfactory system has the strongest direct 68 00:04:49,279 --> 00:04:52,359 Speaker 1: line to the hippocampus and the amygdala, which are the 69 00:04:52,440 --> 00:04:56,160 Speaker 1: memory and emotional centers of the brain. This is why 70 00:04:56,240 --> 00:05:00,680 Speaker 1: sent memories can evoke such powerful feelings of nostalgia. A 71 00:05:00,800 --> 00:05:03,680 Speaker 1: smell can carry us back to a specific time and 72 00:05:03,800 --> 00:05:07,480 Speaker 1: place in ways that conscious thinking and remembering just can't. 73 00:05:08,360 --> 00:05:11,000 Speaker 1: That might explain why we find the smell of baby 74 00:05:11,000 --> 00:05:15,000 Speaker 1: powder so soothing. It summons feelings of security and love 75 00:05:15,200 --> 00:05:18,760 Speaker 1: from deep in our earliest memories. But even that smell 76 00:05:18,880 --> 00:05:23,320 Speaker 1: appears to have cultural variations. Americans associate the new baby 77 00:05:23,360 --> 00:05:27,440 Speaker 1: smell with vanilla and powdery sense, while the French associate 78 00:05:27,480 --> 00:05:31,520 Speaker 1: babies with the scent of orange blossoms. For some people, 79 00:05:31,680 --> 00:05:34,560 Speaker 1: the smell of sunscreen is a stress reliever since it 80 00:05:34,600 --> 00:05:37,039 Speaker 1: reminds them of care free summer days at the beach, 81 00:05:37,720 --> 00:05:40,640 Speaker 1: and so if work is stressing you out, consider stowing 82 00:05:40,640 --> 00:05:43,239 Speaker 1: a squeeze bottle of sp of fifty in your desk. 83 00:05:51,000 --> 00:05:53,520 Speaker 1: Today's episode is based on the article what makes a 84 00:05:53,560 --> 00:05:56,640 Speaker 1: sense soothing on houseuff works dot com, written by Dave Rouse. 85 00:05:57,000 --> 00:05:59,320 Speaker 1: Brain stuff It's production offi Heart Radio in partnership with 86 00:05:59,320 --> 00:06:01,400 Speaker 1: how Stuff Works to dot Com was produced by Tyler 87 00:06:01,440 --> 00:06:04,240 Speaker 1: Playing and Ramsay Young. Four more podcasts from my heart 88 00:06:04,279 --> 00:06:07,200 Speaker 1: Radio visit the i heart Radio app. Apple Podcasts or 89 00:06:07,240 --> 00:06:09,000 Speaker 1: wherever you listen to your favorite shows.